Fix for the setting of the execute permissions on the grace2images.py scripts.
The problem was identified in the post at
http://thread.gmane.org/gmane.science.nmr.relax.devel/3953/focus=4000 and
This is within the relax_disp.plot_disp_curves user function after the grace2images.py script has
been created. The commit matches the changes of r20213 from trunk for the Modelfree4 batch script.
